Kerria shrubs (Kerria japonica) are small ornamental plants. Native to Japan, this shrub is also referred to as the Japanese rose. Identify outstanding features like its prized blooms and bright, long-lived foliage color. Identify care requirements and appropriate hardiness zones for successful growth. Kerria shrubs add vibrant splashes of color to the home garden all year long.
Kerria shrubs display showy, single or double flowers in a variety of hues. From vivid yellow-gold to yellow to white, color depends on the cultivar, according to the University of Illinois Extension. Flowers measure approximately 1 1/2 inches in diameter and display five petals per bloom from April through May. Flowers are often repeat bloomers and color may fade in excessive sunlight.
This clumping, round shrub displays smooth branches that resemble stems in a vivid green color. Color lasts all winter long, making the kerria shrub's foliage a colorful addition to a winter landscape, according to the University of Illinois Extension. The green leaves displayed in spring darken and then either become yellow or drop from the tree in autumn without color change. Kerria shrubs reach a height of 5 to 8 feet with a width of 6 feet.
Though kerria shrubs are not highly susceptible to diseases, keeping them vigorous is ideal for resisting occasional problems as well as for successful development of vivid color. Grow kerria shrubs in partial to full shade. Maintain moist, well-drained soil; kerria prefers fertile loam soil. Kerrias are widely planted in borders and thrive in shaded areas like those covered by trees. Plant in USDA hardiness zones 4 to 9, according to the University of Illinois Extension.
Different varieties of kerria shrubs provide greater selection options for the home garden. Golden guinea displays large blooms measuring up to 2 inches across with extended bloom time. Pleniflora is the most widely planted cultivar and displays double spherical flowers in orange-yellow; plenifloras grow to a height of 8 feet tall. Konshu is a bit smaller, growing to a height of 5 feet with a width of 3 feet; this arching cultivar displays yellow flowers with 2-inch diameters, according to the University of Illinois Extension.
Kerria shrubs do not need heavy pruning, though they will tolerate it, according to the University of Illinois Extension. Twig dieback may occur from extremely low winter temperatures; central twig dieback often occurs due to soil drainage problems. Avoid waterlogged soil and prune areas affected by dieback. Additionally, remove dead plant parts for successful development of new growth. Mildly susceptible to diseases like leaf spot, keeping your plant lightly pruned allows for the development of a sturdy shrub.